The owner dropped the far sheet ring. Remove it from the streaming path:
- UVoxelMarchingCubesMesher::GenerateSheetMesh (declaration + definition);
- sheet-tile branches in LoadTile / GenerateTileResult / SyncRemeshTile and
the bSheetTile / SheetChunkZ / Hole* parameters;
- the SheetHole* XY-hole state and its per-crossing re-queue block;
- VF_MaxMarchingCubesLevel (equal to the clamped MaxClipLevel without sheets);
- the sheet-only band arming and the 'sheet' field of the desired-level
startup-trace events (no tool reads it).
AVoxelWorld now always passes bFarSheetRing=false to the tile selector, and
the descendant index covers levels up to the MaxClipLevel clamp (8) instead
of the old sheet maximum (12); no tile above 8 can exist any more.
Kept on purpose: UVoxelSettings::bFarSheetRing / FarSheetSpanLevels
(UPROPERTYs, now marked unused), the voxel.TestFarSheetRing switch and the
far_sheet_ring / sheet_tile fields the test harness compares (sheet_tile is
always false), and the selector's sheet parameters in
VoxelClipmapDesiredTiles.h, which two automation tests still exercise.